# Interactive Effects of Light Intensity and Nitrogen Supply on Shoot Emergence and Associated Photosynthetic Traits in Dendrocalamus latiflorus

## TL;DR

This study explores how light and nitrogen affect bamboo shoot growth, showing that their balance is crucial for optimizing bamboo cultivation.

## Contribution

The study identifies key photosynthetic traits and optimal light-nitrogen interactions for promoting shoot germination in Dendrocalamus latiflorus.

## Key findings

- Photochemical quenching is the most critical photosynthetic trait for shoot bud germination.
- Low nitrogen with 10% light and high nitrogen with 40% light maximize shoot germination.
- Balanced light and nitrogen supply during the shooting period enhances shoot growth in bamboo.

## Abstract

Fertilization and light are the key factors affecting the development of plant lateral buds. Therefore, maintaining the optimal balance of light and nitrogen is essential to promote plant growth. A key objective of research in this field is to provide practical guidance for nutrient management in bamboo cultivation systems. Our study found that chlorophyll, chlorophyll a/b, photochemical quenching, sucrose, and leaf nitrate were the main photosynthetic characteristic factors, and photochemical quenching was the most important internal regulatory factor. From the perspective of the development stage, nitrogen fertilizer plays a dominant role in promoting bud germination at the early stage of germination; in the middle stage of seedling emergence, light intensity and nitrogen significantly affected the development of new shoots. In the later period, the light intensity was the dominant factor. Thus, balanced regulation of light and nitrogen supply in the understory during the shooting period can effectively enhance shoot germination and growth in Dendrocalamus latiflorus.

Investigating light–nitrogen interactions during bamboo shoot bud germination of Dendrocalamus latiflorus provides a theoretical basis for regulating shoot emergence through optimized light intensity and nitrogen supply. This study further elucidates how such coupling effects can guide stand density adjustments in bamboo plantations. Additionally, it provides actionable insights for improving nutrient management strategies in practical bamboo cultivation systems. This study evaluated the effects of different nitrogen levels (1.5, 4.5, and 7.5 g·clump−1) combined with varying light intensities (10%, 40%, and 100%) on shoot germination and physiological characteristics of bamboo. Two-way ANOVA revealed a significant interaction between light intensity and nitrogen concentration on bamboo shoot bud germination (p < 0.05). Under low nitrogen conditions, bamboo shoot bud germination was highest (3 buds·clump−1) at 10% light intensity. However, under high nitrogen conditions, the highest germination (4.75 buds·clump−1) occurred at 40% light intensity. Moreover, leaf carbon, nitrogen, and starch contents were positively correlated with shoot bud germination. Pearson correlation and path analyses indicated that total chlorophyll, chlorophyll a/b, photochemical quenching coefficient, sucrose, and leaf nitrate were the main photosynthetic traits associated with bamboo shoot bud germination. Among these, the photochemical quenching coefficient was the most critical factor. Based on this, the nitrogen management, nitrogen utilization, and low-light adaptability of D. latiflorus could be optimized.